Author Topic: Boss CE-2 troubleshooting  (Read 941 times)

duck_arse

Re: Boss CE-2 troubleshooting
« Reply #20 on: September 17, 2021, 10:19:54 AM »
https://pdf1.alldatasheet.com/datasheet-pdf/view/172151/ONSEMI/BF256A/+05327_VLLS.xKdGKYwEI+/datasheet.pdf

the Onsemi datasheet for pinout [end gate pin]. don't look at the motorola datasheet for that BF256, it has a real mess of a pinout diagram.
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znanjeiimanje

Re: Boss CE-2 troubleshooting
« Reply #21 on: September 18, 2021, 05:02:09 PM »


Quote
Point 2: Could be my understanding as I am just starting to deal with pedals, but frequency on pin 1 vs pin 2 is a fixed 77, while vs pin 7 it's 100
Put the depth fully CW and monitor the frequency of the LFO (pin 7 of the MN3101) as you increase the rate. Verify that it increases as you turn the rate up. Same thing with pins 2 & 4 which are what drives the MN3007. If you observe identical frequencies on pins 2 & 4 you know the clock is fine.


Quote
Point 3: I hear no sound at all
Prof that the clock isn't driving the BBD or the BBD is dead. Did you try adjusting VR3 as you audio probed the BBD's output? Moving forward; suspect the clock or LFO and check the frequency as you adjust the rate. Instructions in Point 2.
Could have blown something from the shorted connection mentioned in your first post. So it would be best to test these externally. If you have a breadboard I have a very simple circuit I use to quickly verify all of my BBDs & clocks. I'll post it if you think it'll be useful.

The thing is, none of us know exactly what's going on with your CE-2. But the fact that there's no signal coming from the BBD's output is THE place to focus on right now. Soldering and resoldering them is not wise. They should definitely be socketed.

I have done as instructed and indeed, the frequency is increasing on Pin 7 of MN3101. Also, on MN3101 I have the same frequency on pins 2 and 4 of MN3101.

Would be great if you could share the layout to check the BBD and clocks would be great, so I can make it these days and test this. Thanks a lot for the help!

Kevin Mitchell

Re: Boss CE-2 troubleshooting
« Reply #22 on: September 20, 2021, 04:07:29 PM »
Ahh I found it so I don't have to redraw it.
Here's a more simple schematic but not for audio. It just shows if the BBD has any life in it (able to pass signal). Pin compatible for MN/V3204, MN3206, MN/V3207, BL3208 (8DIP package) & MN3209. The diode at the output is an LED and there's a switch (or just use a jumper) to change the input's state.

This was for testing a MN3102 & MN3207. So just swap the power pins for the BBD (clock in pin to pin compatible) and it'll work. I'll update this post tonight to verify as it's been a while since I had used it on those devices.
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znanjeiimanje

Re: Boss CE-2 troubleshooting
« Reply #23 on: October 07, 2021, 10:17:17 PM »
Ahh I found it so I don't have to redraw it.
Here's a more simple schematic but not for audio. It just shows if the BBD has any life in it (able to pass signal). Pin compatible for MN/V3204, MN3206, MN/V3207, BL3208 (8DIP package) & MN3209. The diode at the output is an LED and there's a switch (or just use a jumper) to change the input's state.

This was for testing a MN3102 & MN3207. So just swap the power pins for the BBD (clock in pin to pin compatible) and it'll work. I'll update this post tonight to verify as it's been a while since I had used it on those devices.

Thank you very much for the help. I have finally gotten a hold of a breadboard and hooked it up. Would it be too much to ask how to proceed with the check? Do you have any values I could have at particular points?

znanjeiimanje

Re: Boss CE-2 troubleshooting
« Reply #24 on: November 13, 2021, 10:57:49 AM »
An update:

Unfortunately I couldn't get the BBD circuit above to work (better say I couldn't figure out how to test it exactly), but meanwhile got a hold of another working CE2. Swapped MN3007 and nothing. After that swapped MN3101 and it worked. The chorus does sound a bit weaker than the working CE2, but I guess this is due to the bias which I will have to do once I get a hold of a MN3101.